A conventional optical recording or reproduction device comprises an SRAM or a DRAM storage for correction and track buffering in frontend ICs of optical recording or reproduction devices.
The SDRAM is built around two banks of memory, which are accessed by particular pipelined address logic. In contrast to the normal DRAMS addressing can be done in parallel to the data operation and depending on the mode chosen a burst of consecutive locations is operated. This accelerates the speed compared to the common DRAM drastically, on the other hand needs some additional buffering and address control.
SDRAM is an acronym for Synchronous DRAM that means a DRAM technology that uses a clock to synchronize signal input and output on a memory chip. The clock is generated in the driving IC and derived from it's system clock so that the timing of the memory chips and the timing of the driving IC are in synchronization. The data streams for storing, correction and track buffering in frontend ICs of optical recording or reproduction devices are due to several different modes, asynchronous data streams and are not designed in a way that it can be handled directly within an SDRAM because it has no defined burst structure as well as a constant speed as it is commonly used in computer applications. An adaptation of the streams for SDRAM usage is therefore necessary.
A system decoder for high-speed data transmission with track buffer for an optical disc player has been disclosed by GB-A-2 321 334. Said system decoder includes a track buffer memory, a first FIFO memory for receiving data descrambled and error-detected and outputting the data by a unit of plural words, a second FIFO memory for receiving data from the track buffer memory and outputting the data by the unit of plural words, and a track buffer controller writing data in the first FIFO memory into the track buffer memory in a page mode, and reading the data written in the track buffer memory in a page mode to output the read data to the second FIFO memory. The track buffer memory includes a data area into which main data is written, an error information area into which error information for the main data is written and a microcomputer area into which a microcomputer of the optical disc reproduction apparatus writes data.